Perhaps even colder than last week, when southern England experienced its chilliest February night for 10 years, with temperatures of -9.4C recorded in Benson, Oxfordshire, and -9.5C in Redhill, Surrey.

The Gulf Stream, which sweeps warm water across the Atlantic from the Caribbean, is responsible for keeping temperatures higher in the UK and north-west Europe. This oceanic conveyor belt is driven by differences in temperature and salinity of seawater, but there are fears that the melting Greenland ice cap and increased rainfall could make the Gulf Stream shut down, as in the film The Day After Tomorrow.

"Based on climate simulations we think that UK winters would be around 5-10C colder on average if the Gulf Stream shut down," says Michael Vellinga, of the Met Office's Hadley Centre for Climate Prediction and Research. For those who can remember back that far, this would make the average UK winter feel more like 1963, when February temperatures hovered around -5 C. But there is no need to rush out and invest in more thermals yet. "We don't think that a shutdown is very likely over the next 50 to 100 years, but we can't rule it out," says Vellinga.